[hex] Use libhex to encode hex string in avmd and apexutil

Bug: 239413416
Test: atest avmdtool_tests libapexutil_rust.test
Change-Id: I58fcc32f62bea1cd34b171ac336a1ed13f5735b8
diff --git a/avmd/Android.bp b/avmd/Android.bp
index 6d91b59..0b87a7b 100644
--- a/avmd/Android.bp
+++ b/avmd/Android.bp
@@ -9,8 +9,8 @@
     srcs: ["src/lib.rs"],
     prefer_rlib: true,
     rustlibs: [
+        "libhex",
         "libserde",
-        "libapexutil_rust", // TODO(b/239413416): Remove this after adding hex
         "libapkverify",
     ],
 }